North...

Every time I head back towards the 49th parallel I realize how much I miss the North.  There’s no question that part of the attraction is the smell – it hit me hit me hard as I got out of my car in the parking lot of the Holiday Inn in Tilton, NH.  Softwoods, lakes, smoke, and I don’t know; just a bunch of olfactory data that told my brain I was close to home.

I was up in New Hampshire with the F1 rolling chassis to install my newly rebuilt motor at BCM and spend some time ion the dyno with Kyle Thompson experimenting with jetting and cam timing – something I never got around to when the 853 motor was first rebuilt.  The motor was being rebuilt ‘cause I began picking long, thin, curved slivers of material off my magnetic drain plug at the end of the ’07 season and had enough by the middle of ’08 to make a very thin ring that measured 40mm – the OD of the crank at the shim.  This meant that Guy Martin had put too much preload on the crank when he built it or just botched the shimming altogether with the resulting disintegration of shims and bearings.  I could feel the vibration last time out (October ’08) and knew that the “Best Before Date” had been exceeded.

Zip back to late 2004, when we (Guy Martin (MBP), Adam and I) started the project with a view to building a robust, high-revving version of what the Ducati factory had done at the end of the F1’s lifecycle using modern bits and creative machining.  The inspiration came from the Japanese F1 community; who had shoehorned a 900SS with F1 heads into a later version TT1 frame, but we wanted to retain the original F1 short stroke.  Guy came up with the used 996 rods and 748 crank and did a set of his Testarossa heads (which meant that after he lost the big valve argument with me, they were sent off to Patrice for porting), BCM provided the Pistal / Millennium 944 kit, I sourced a donor 900SS engine and generally hemorrhaged cash while Adam set to the machining of the heads, barrels, cases and wrist pin bushings.  When all the components were back from their respective processes, Guy did the final assembly.  Start-up didn’t go to well with the motor puking oil within 4 minutes of breathing its first breath.  I pulled the front cylinder to find that we had machined off the seat for the front return o-ring and noticed as well, some serious scoring of the cylinder.  At the end of a day-long thrash, we got the bugger running and I’ve been surprising early 4-valve Ducatis with it since.

Prior to rolling into the parking lot at BCM last week, Kyle and Leslie had been giving me weekly updates on the motor rebuild and what I knew even before I set off on the nine hour drive North was that Guy had seriously messed up both the gearbox and crank shimming and had set the initial ring end gap incorrectly.  Kyle whipped the cylinders back to Millennium for a refresh and had installed new rings.  The main bearings were shot and the crank was at the far end of flopping around with one race spun in the case.  Even uglier was the squish setting on both combustion chambers – close enough that he couldn’t believe the pistons weren’t whacking the heads.  Actually, the squish measured at the crown of the piston was OK – the problem was with the mismatched piston / combustion chamber profiles.  We have a piston designed for a 900SS bathtub combustion chamber trying to mate the an old F1 hemi combustion chamber and the diminishing difference in angles meant that the squish set safely at the tightest point in the upper ramp should have made for a very conservative number at the crown (as it does now).

But that’s enough Guy bashing..

I love hanging out at BCM Ducati.  There’s a fine vibe about the place and while I’m not entirely sure why I’m treated like family, I certainly enjoy having the run of the shop and the opportunity to hang and work with the talent.  Although Kyle’s choice of music doesn’t fit his clean-cut, All-American image; the death metal and hard core rap wafting through the shop somehow didn’t quite drive me to drinking.  In fact, when Pandora went into sleep mode, the atmosphere just didn’t feel right.

Kyle walked me through the build process and set me up with a bench in the main shop so I could install the motor and get the bike ready for start-up and while the process would likely take me about 2 hours in my shop with my stuff – I burned about four hours working with a different set-up to get to the point where I could add oil and gas and push the button. 

And then it would only run on one cylinder.

Kyle found some sketchy connections to the igniters, but that proved to be a fruitless discovery.  No – he wanted me to pull the engine side cover and check the connections to the pick-ups.  I protested.  “I rewired them 3 years ago… “  But really; between us girls, I just didn’t want to go through the process of removing the front carb, exhaust system and engine cover.  You see in old age I’ve just completely lost my tolerance for things that don’t work right first time.  But, grumbling under my breath while I cursed the now truly evil metal playing on Pandora – I pulled all the stuff of to find the front cylinder pickup wire broken so close to the plastic housing that soldering was off the menu.  Ah, the good news?  Problem found.  Next good news?  They had a $200 NOS replacement set sitting in inventory.

And then it ran on two cylinders.  And beautifully I might add.  With the end of the megaphone temporarily blocked off with a well-placed boot sole there was hardly any mechanical noise from the engine – save for the rattling of the carb slides and clutch plates.  So, I spent the balance of the day happily running the engine through heat cycles and futzing with carb synch.  Kyle switched from metal to rap….

The next day started with more heat cycles before awakening the dyno room from its winter slumber.  Other than clearing out a few bikes, this really amounted to Kyle dusting off and rebuilding the O2 pump while I set up a propane heater to warm the room.

We did a couple of easy passes and heat cycles with a view to fine tuning the air/fuel in the drivability ranges and much to my surprise, found that the idle settings were on the money and the needle was in the ballpark.  Unfortunately, messing with the needle on a Mikuni 41mm pro Series flat slide is right up there with filling out your own tax return.  The needle is held in place by a collar that’s fixed with two really small Phillips screws and this affair is underneath a plastic collar that keeps the cable properly seated.  Both of these annoying little items are of course under spring tension and without undoing the idle adjusters, you’re left with less than 2” of room to get at the stuff once you run the spring up the cable and hold it in place with a forceps.  This is maddening stuff best left to deft Orientals with small fingers that still have some feeling left in them.

But a couple of needle position changes on a slightly richer needle put us in the sweet spot and we warmed the bike up for a first baseline pass at full throttle.  Both Kyle and I were surprised to see almost 85HP (81.4 corrected) and a whopping 60.9ft/lbs Torque on the first go.  We upped the main jets two sizes and moved the cam timing to open the intake 2 degrees earlier and got the best run of the day: 87.5HP (85 corrected) with 63 pavement rippling ft/lbs.  We went another two degrees hoping to validate some of the opinions that promised more HP if we got the lobe centers up in the teens, but we could see where we were heading on the first attempt.  Yes, there was more HP available if we continued to open the intake earlier, but it came with the costs of higher revs and a significant loss of torque.  So 108 and 109 degrees at lobe centers became the hot set-up.

For the finale, we bolted on the WhisperJet baffled megga I use at Calabogie and again the jaws were on the floor as the home-made baffled pipe made almost the same peak HP as the open megga.  Unfortunately, the bad news was that WhisperJet robs the motor of 7ft/lbs in the process, but the A/F showed the needle on the lean side, so I might be able to pull a bit of that back by raising the needle a touch.

All in all, a truly enlightening and pleasant experience.  The jetting and cam timing gave me the 5HP increase I was looking for and even more punch than the bike had before the changes so I’m chomping at the bit to try it out on the track.  Unfortunately, two weeks ago I joined to 8.2% of Americans who got nailed in the recent run of layoffs so the MAD VIR event in two weeks is off the menu.  It’ll be Mosport in May with any luck.

A huge load of thanks to Kyle Thompson for his exceptional work and advice, to Leslie Grossman for his gracious hospitality and to Miles and Frick for making me feel at home from the moment I rolled into the BCM parking lot.

My trigger finger’s so itchy….